A Case Report of a Cutaneous Mucinous Reaction Associated with Erlotinib Therapy Used in the Treatment of Metastatic Tonsillar Sinus Squamous Cell Carcinoma.

Cutaneous mucinoses are a diverse group of diseases that are occasionally seen in the context of an adverse drug reaction. We report the case of a 59-year-old male who presented with an asymptomatic, acneiform rash on his forehead, scalp, nose, upper chest, and upper back that had developed after treatment with erlotinib therapy used in the treatment of metastatic tonsillar sinus squamous cell carcinoma. Biopsy of these lesions demonstrated atypical histology that had features of both follicular mucinosis and myxedema. This histologic phenomenon is a rare drug reaction that has not previously been described in association with erlotinib.

Characterization of Cutaneous Adverse Events Associated With PI3K Inhibitors in 11 Patients.

Introduction: Phosphoinositide 3-kinase (PI3K) inhibitors are a new class of cancer therapeutics that inhibits one or more enzymes in the PI3K/AKT/mTOR tumor growth pathway. As compared to other tyrosine kinase inhibitors, there is evidence that PI3K inhibitors have a higher incidence of severe cutaneous adverse events (CAEs) ranging from 2-21%. There is a lack of further characterization of clinical trials and management options for these CAEs. Methods: A retrospective chart review of our institution's records between January 2015 and May 2019 was conducted; electronic medical records were queried by using a pharmacy database and ICD-10 codes for patients receiving PI3K inhibitor who experienced CAEs during therapy. These CAEs were characterized by two board-certified dermatologists at a major cancer center. Results: Eleven patients were identified as having 12 cumulative CAEs. Average time to rash onset was 4 weeks, and the most common identified rashes were eczematous (25%) and morbilliform (17%). Four patients experienced a dose delay, and one patient immediately discontinued their PI3K inhibitor. Conclusion: Although most CAEs caused by PI3K inhibitors in this study were limited to grade 1-2 and were controlled with topical corticosteroids and oral antihistamines, a number of patients experienced dose impact. This highlights the dermatologist's role in managing and minimizing interruption of therapy while maintaining quality of life.

Linear terra firma-forme dermatosis of the midline back.

Terra firma-forme dermatosis (TFFD) is a benign and likely underdiagnosed disorder with relatively few reports in the literature. A 46-year-old woman presented to our clinic with a 3-year history of linear TFFD extending from the upper sacrum to the midline upper back. It initially was thought to be acanthosis nigricans or lichen simplex chronicus, and a topical steroid cream was applied without success. The lesion ultimately was removed by rubbing with isopropyl alcohol, which confirmed a diagnosis of TFFD. Due to its ability to mimic other skin diseases, TFFD should be considered when patients present with hyperkeratotic hyperpigmented lesions.